The data memory capacity of portable battery driven apparatus such as mobile telephone handsets, has increased significantly and it is envisaged that mobile telephone handsets may have mass memories with a capacity of the order of Gbytes or more in due course. As a result, large amounts of data may be downloaded over the air to the handset for storage in its memory. However, the bandwidth of the mobile wireless network is limited so that the delivery of for example a 30 Mbyte file over a general packet radio system (GPRS) network typically would occur at 40 Kbit/sec and would take approximately 100 minutes. Thus, if the battery of the mobile handset has insufficient capability to support the download over this period, the downloading process will fail and battery resources will be wasted.
Also, the memory of the portable apparatus may become fragmented over time and so a defragmentation housekeeping routine should be carried out. As known in the art for computers, this involves a systematic scan of the memory to determine where various data blocks are loaded, so as to identify unused fragmented portions of the memory and then the data is reloaded into contiguous blocks so as to create unfragmented memory regions for future use. The defragmentation process can take a significant time, of the order of 15 minutes or more depending on the condition of the memory and if the battery has insufficient capacity to complete defragmentation process from beginning to end, the process will fail and will have to be started again from the beginning, wasting battery resources.
Also, with increased memory capacity in the portable apparatus, it becomes desirable to provide a memory backup to prevent accidental data loss, for example of digital photographs, videos and other data. One proposal is to upload the data from the portable apparatus over the air to a remote server in the Internet. The uploading uses up battery resources in a similar manner to the downloading of data and so if the battery has insufficient capacity to complete the upload, the uploading process will fail and waste battery resources.
The present invention seeks to overcome these problems.